Dear mikalou,
Thank you very much for sharing! Just what I needed! I applied your changes to func.cart.php but use a different code for cart.tpl since I had no loop in there. It has a foreach statement instead (v4.2). I simply use in cart.tpl:
Does the trick for me
__________________
www.qualitylamps.eu
X-Cart Gold 4.1.8, PHP 5.2.6, MySQL 5.0.51a, Apache 2.2.9
www.vervangjelamp.nl
X-Cart Gold 4.2.0, PHP 5.2.6, MySQL 5.0.37-standard, Apache/2
Sorry for the weird user name, I registered it by mistake 